


Things I Don't Want To Know For $400, Alex

by ThroughTheTulips



Category: Supernatural
Genre: Alpha Dean, Alpha Sam, M/M, but pretty much the crankiest least omega-y omega, castiel doesn't understand things, omega cas, what is sam's life even
Language: English
Status: Completed
Published: 2016-02-16
Updated: 2016-02-16
Packaged: 2018-05-21 01:48:30
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,297
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/6033589
Author URL: https://archiveofourown.org/users/ThroughTheTulips/pseuds/ThroughTheTulips
Summary: <blockquote class="userstuff">
              <p>Jimmy was a beta, so it's a surprise all around when Human!Cas turns out to be an omega. A really, really awkward surprise (at least for Sam).</p><p>Inspired by SillyBlue's tumblr post from forever ago:<br/>"I’m in the mood to think about oversharing Cas again who doesn’t understand (or care) that it’s inappropriate to share details of his sex life with others.<br/>Or maybe, a variety of this could be omega!Cas who is not shy at all to talk about the “mysteries of the omega body” and the annoying parts of it.<br/>But it’s almost 2 AM so I should got to bed."</p><p>(Set while Castiel was human and living in the bunker, because shut up that happened here and it was cozy and magical.)</p>
            </blockquote>





	Things I Don't Want To Know For $400, Alex

**Author's Note:**

  * For [SillyBlue](https://archiveofourown.org/users/SillyBlue/gifts).



Sam was heading to the bunker’s gym, mind focused on the yoga exercises he’d been studying, when an irritated huff drew his attention. He looked up to find Castiel at the end of the hall, an overloaded laundry basket in his arms. “Everything okay?”

The former angel scowled. “No.”

“Anything I can- whoa,” Sam interrupted himself as the smell hit him. He felt the back of his neck heat. “Uh. You’re really getting the whole, uh, human experience, aren’t you?”

“So it would seem.” Castiel shook the basket of sheets, sending the powerful scent of omega pre-heat wafting down the hall. “Jimmy was a beta. Needless to say I was unprepared to wake up covered in fluid. The sensation is deeply unpleasant.”

The casual words nearly made Sam choke on his tongue. He rubbed his neck. “Are, uh, I mean, do you need clean sheets or… anything?”

“I know where the sheets are.”

“No, I mean-” The hunter took a deep breath. “Cas, do you know how to- take care of yourself?”

Castiel tilted his head, squinting. “I haven’t set fire to the kitchen in over a week and I’ve bathed recently. If there is some other human activity I’m neglecting-”

“During heat,” Sam blurted. God, how was this his life? “There are things you need to get through heat without an alpha. Uh, tools. Omega tools.”

The blue eyes cleared. “Oh, that won’t be necessary. Dean will be assisting me during my heat.”

What? “You talked to him about this?”

“As soon as I realized I was reformed as an omega,” Castiel said, pushing past in a cloud of pheromones. “It’s possible to get through heat without an alpha, but intercourse obviously offers the most relief. Would you mind telling him my heat is beginning? I should have half an hour or so before I need to be penetrated and I want to throw these sheets in the laundry.”

Sam’s whole body burned with secondhand embarrassment. “Uh, yeah, I’ll text him. Good luck.”

“Luck should not be necessary. Dean has an enormous amount of carnal knowledge, and when I rebuilt him I noticed his knot is larger than average. I expect it will be very pleasant.”

“That’s… great,” the hunter said, cringing internally. “I mean, uh, have fun?” He turned and ran while the running was good.

 

He didn’t see Castiel for four days. Every so often Dean shuffled into the kitchen, bleary-eyed and smug, and cooked ridiculous amounts of food before disappearing again. Sam kept his headphones on and tried not to think about it.

On the fourth day he screwed up enough courage to knock on Dean’s door. His brother answered on the fifth try, sheet draped loosely around his waist. “Something on fire, Sammy?”

“It’s been half a week,” the younger man whispered. “Heat is only supposed to last two days with an alpha, Dean. Something must be wrong. We need to take him to a doctor.”

“I’m fine,” Castiel rasped from the bed. He seemed utterly unconcerned by his nudity or the red marks covering his body. Hickies. Fuck, those were hickies _Dean_ had put on him, _gross_. “This body is experiencing its first heat. Those can be significantly longer even with regular knotting, and Dean has been very diligent about that.”

Deer leered. “Yeah, I have.”

Sam threw his hands up, backing away. “Fine, okay, I don’t need details. I’ll go.”

The omega frowned and slid off the bed, face creased with worry. “Is everything all right, Sam?”

“I was just checking on you, okay?”

Castiel came closer, dangly bits dangling and thighs wet with _whatever_ and Sam was _not looking_. “You smell upset.”

Dean, little shit that he was, grinned. “Maybe he’s jealous.”

Which, no, but Castiel’s frown deepened. “I was unaware you were physically attracted to me. My apologies, Sam. I’ve already begun my heat with Dean, and changing sexual partners would extend it. I have no interest in drawing this out. My nipples are swollen, I’ve experienced four emotional states in the last hour, and every part of my body is covered in procreational lubric-”

“Stop!” Sam blurted desperately. “I’m not jealous, and I really don’t want to know any of this. People don’t _talk_ like that, Cas, not to alphas they aren’t sleeping with. It’s like taking off your pants in public, okay? Don’t you know any other omegas you can talk about that stuff with?”

To his horror the blue eyes filled with tears. Dean lost his teasing smile. “Damn it, Sammy, now he’s crying. Say you’re sorry.”

“It’s fine,” Castiel sniffled. “I told you, the hormones are problematic. It seems I am the one who should apologize for making you uncomfortable. I will try to be more considerate in the future.”

He stepped forward, arms out for a hug. Dean snarled at the same moment Sam leapt back. “Uh, can I have a rain check on that?” he asked, watching his brother warily. “You’re kind of- marked territory at the moment.”

The former angel looked at Dean and tilted his head. A sly, utterly non-angelic smile slid across his face. When he spoke his voice was- shit, that was a sex purr, Castiel was sex purring _right in front of Sam_. “Am I? These must be fading if I’ve forgotten.”

Dean growled, one arm hooking around Castiel’s waist to tug him closer, and Sam was done. He squeezed his eyes shut and slammed the door before he could see any more.

That was it, he didn’t care if the bunker caught on fire. Nothing in heaven or hell could make him go back in that room (and he should know). Dean and Cas would just have to work things out themselves.

 

The next morning Castiel emerged from Dean’s room, clean and rational again. Sam breathed a small sigh of relief as everything returned to normal (or as normal as life ever gets for them). Maybe the lovebirds snuggled a little, maybe they were a little disgusting, but Sam was happy for them. It was an incredible relief to know things were settled.

Or so he thought.

Three months later Sam came down to find Dean and Castiel arguing over breakfast. They stopped when he came in. Dean jammed a stack of bacon in his mouth and spoke sulkily around it. “Do whatever you want, all right? It’s your heat.”

 _Oh no._ The first wisps of early heat hit Sam far too late. He cleared his throat. “Oh, uh, I guess I lost track of time. Just let me grab some breakfast and I’ll be out of your hair.”

“That’s not necessary,” Castiel told him. “I would like to invite you to assist me this heat.”

The alpha’s brain ground to a halt. He shot a glance at his brother. “Are you guys breaking up? You seemed fine.”

“Our relationship is sound, thank you. After Dean’s words last time I realized this could be viewed as an unbalanced division of resources, and I have no interest in being yet another problem driving you two apart,” Castiel said serenely. “So, although I love Dean, I am willing to rotate-”

“Okay, nope, do not finish that sentence,” Sam interrupted, snatching his jacket from the chair where he’d left it last night. “I am going to Jody’s for the week. You guys clean up after yourselves, okay?” He turned to leave, then spun back. “And Dean, for God’s sake bite him already. I’m not sharing your mate, okay, he’s like my brother.”

An expression of mingled surprise and pleasure lit Castiel’s face, but Sam didn’t stay to talk about it. Dean’s possessive growl had him running for the car without so much as grabbing a bag. There were some things a brother just didn’t need to see.

Again, anyway.

 

**Author's Note:**

> Thank you to the lovely SillyBlue for the loan of the prompt and for reassuring me it isn't creepy to still have it lying around a year later.


End file.
